The invention proceeds from a cell connector of a battery module comprising a first connecting region formed for electrically conductive connection to a connection terminal of a first battery cell and a second connecting region formed for electrically conductive connection to a connection terminal of a second battery cell, wherein the cell connector has at least one first layer element and one second layer element, and a second surface of the first layer element and a first surface of the second layer element are connected to one another. Furthermore, the invention also relates to a method for producing a cell connector of this kind. The subject matter of the present invention is also a battery module comprising a cell connector of this kind.
It is known from the prior art that batteries, in particular batteries of electric and hybrid vehicles, as well as lithium-ion batteries, in particular, consist of at least one battery module or advantageously also of a plurality of battery modules.
Furthermore, a battery module preferably has a multiplicity of individual battery cells, which are interconnected between themselves with the battery module, wherein the individual battery cells can be electrically interconnected with one another in series and/or in parallel by means of cell connectors.
In this case, cell connectors preferably formed from aluminum connect connection terminals of two battery cells to one another.
Relative movements between individual battery cells of the battery module and hence also between the connection terminals thereof on account of shock loads acting on the battery module as well as on account of volume changes of the housings of individual battery cells, referred to as swelling, induce internal mechanical stresses in the cell connector or stresses at the connection location between the cell connector and the respective connection terminal, which, over the lifetime of a battery module, can lead to safety-critical fatigue fractures in the cell connector.
In this case, it is known from the prior art that the cell connector may comprise a compensation region, for example having a wave shape, or also that the cell connector is formed from a plurality of individual films.
On the one hand, in this case, cell connectors are embodied to be as thin as possible in order to produce a material-bonded connection between the connection terminal of the battery cell and the cell connector with the lowest possible energy input and thus to be able to minimize the heat input into the battery cell. In this case, connections of this kind are typically produced using laser welding.
On the other hand, cell connectors require a sufficient current-carrying cross section for the conduction of the electric current between two voltage taps of different battery cells.
In known solutions, these two demands on a cell connector can in this case often conflict with one another.